1. Field of the Invention
The present invention generally relates to a semiconductor device, a method of manufacturing the semiconductor device, a flip chip package having the semiconductor device, and a method of manufacturing the flip chip package. More particularly, the present invention relates to a semiconductor device having conductive bumps, a method of manufacturing the semiconductor device, a flip chip package having the semiconductor device, and a method of manufacturing the flip chip package.
2. Description of the Related Art
Generally, various semiconductor fabricating processes may be performed on a wafer to form a plurality of semiconductor chips. In order to mount the semiconductor chips on a printed circuit board (PCB), a packaging process may be performed on the wafer to form semiconductor packages.
One kind of the semiconductor package can be a flip chip package, as an example. The flip chip package can include a semiconductor chip and a substrate disposed to face each other. Pads of the semiconductor chip and pads of the substrate can be electrically connected to each other in one-to-one relation via conductive bumps. An underfilling layer can be formed between the semiconductor chip and the substrate to protect the conductive bumps from external impacts. Thus, a method of manufacturing the flip chip package can include a process for forming the conductive bumps on the pads of the semiconductor chip.
According to a conventional method of forming conductive bumps, a protective layer pattern is formed on a semiconductor chip to expose pads of the semiconductor chip. An under bump metallurgy (UBM) layer is formed on the protective layer pattern to electrically connect the pads and the UBM layer. An electroplating process can be performed on the UBM layer to form the conductive bumps on the UBM layer.
Here, the semiconductor chip can have a guard ring. The guard ring can include a metal layer for preventing a sudden flow of currents or conductive ions into the semiconductor chip.
A trench configured to receive the guard ring can be formed along an edge portion of the semiconductor chip. The guard ring can be formed together with the pads. For example, a metal layer can be formed on an upper surface of the semiconductor chip and an inner surface of the trench. The metal layer can be partially etched to form the pads on the upper surface of the semiconductor chip, and the guard ring on the inner surface of the trench. An insulating layer pattern can be formed on the semiconductor chip. The UBM layer can be formed on the insulating layer pattern.
Therefore, the UBM layer can be formed along the inner surface of the trench. Here, a portion of the guard ring on an upper end of the trench can have a thickness greater than that of other portions of the guard ring on the inner surface of the trench. Thus, a portion of the UBM layer over the upper end of the trench can have a thickness greater than that of other portions of the UBM layer on the inner surface of the trench. As a result, a portion of the UBM layer on a lower end of the trench can have a relatively thin thickness.
The thickness difference of the UBM layer can cause a size difference of the conductive bumps. Particularly, in the electroplating process for forming the conductive bumps, the current may flow through the UBM layer. However, a sufficient amount of the current may not flow through the thin portion of the UBM layer, so that the thin portion of the UBM layer can have an increased resistance. As a result, the conductive bumps on the bumps that are positioned before and behind the guard ring can have different sizes. Here, the conductive bump having a relatively smaller size can have a contact area that is less than that of the conductive bump having a relatively larger size, so that the flip chip package can have bad electrical joint reliability.